1. Field of the Invention
The present invention relates to a fixing apparatus which fixes a toner image on a sheet. The fixing apparatus can be used, for example, in an image forming apparatus like a copying machine, a printer, a facsimile (FAX), and a multifunction peripheral having a plurality of such functions.
2. Description of the Related Art
An image forming apparatus using an electrophotographic method conventionally includes a fixing apparatus which fixes a toner image formed on recording material (sheet) at a nip portion between two fixing members (first and second fixing rotatable members). A lot of toners with improved fusibility have recently been developed. With improved fusibility, toner can be uniformly and favorably melted by a fixing apparatus. This makes the fixed toner layer more uniform and smoother for improved image glossiness.
As a result, an image having higher glossiness and higher image quality than heretofore can be formed on high gloss recording material such as coated paper.
As the fixing apparatus repeats fixing processing, the fixing members tend to be deteriorated in surface properties by edge portions of recording material (both ends in a direction orthogonal to a conveyance direction of the recording material) as compared to other areas. Specifically, the areas touched by the edge portions of recording material tend to be roughened in the surface as compared to the other areas. Such uneven surface properties of the fixing members can appear on the fixed image as uneven image glossiness.
An apparatus discussed in Japanese Patent Application Laid-Open No. 2008-040363 includes a roughing roller (rubbing rotatable member) which rubs the surface of a fixing member. Specifically, the roughing roller rubs the fixing member to make a deteriorated state (surface roughness) of the areas touched by the edge portions of recording material less noticeable as compared to the other areas.
When the roughing processing by the roughing roller finishes and the roughing roller is separated from the fixing member, a line of shavings produced by the roughing processing can appear on the fixing member. Such shavings interfere with favorable fixing processing next time. Specifically, a line of shavings can appear on an image to cause a decrease in image quality.